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From: Hannes Frederic Sowa <hannes@stressinduktion.org>
To: Eric Dumazet <eric.dumazet@gmail.com>,
	jongman.heo@samsung.com, David Miller <davem@davemloft.net>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: [PATCH] ipv6: fix possible seqlock deadlock in ip6_finish_output2
Date: Fri, 29 Nov 2013 06:39:44 +0100	[thread overview]
Message-ID: <20131129053944.GH24171@order.stressinduktion.org> (raw)
In-Reply-To: <20131128192231.GE24171@order.stressinduktion.org>

IPv6 stats are 64 bits and thus are protected with a seqlock. By not
disabling bottom-half we could deadlock here if we don't disable bh and
a softirq reentrantly updates the same mib.

Cc: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
---
 net/ipv6/ip6_output.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 59df872..4acdb63 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -116,8 +116,8 @@ static int ip6_finish_output2(struct sk_buff *skb)
 	}
 	rcu_read_unlock_bh();
 
-	IP6_INC_STATS_BH(dev_net(dst->dev),
-			 ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES);
+	IP6_INC_STATS(dev_net(dst->dev),
+		      ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES);
 	kfree_skb(skb);
 	return -EINVAL;
 }
-- 
1.8.3.1


  parent reply	other threads:[~2013-11-29  5:39 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-11-28  4:17 3.13.0-rc1+ INFO: inconsistent lock state 허종만
2013-11-28  7:18 ` Hannes Frederic Sowa
2013-11-28 17:23 ` [PATCH] udp: fix possible seqlock deadlock Eric Dumazet
2013-11-28 17:36   ` Eric Dumazet
2013-11-28 17:51   ` [PATCH v2] inet: fix possible seqlock deadlocks Eric Dumazet
2013-11-28 18:09     ` Hannes Frederic Sowa
2013-11-29 21:38       ` David Miller
2013-11-28 19:22     ` [PATCH] inet: further fixes of " Hannes Frederic Sowa
2013-11-28 21:01       ` Eric Dumazet
2013-11-28 21:27         ` Hannes Frederic Sowa
2013-11-28 22:19           ` Hannes Frederic Sowa
2013-11-28 23:15             ` David Miller
2013-11-29  5:39       ` Hannes Frederic Sowa [this message]
2013-11-30 16:45         ` [PATCH] ipv6: fix possible seqlock deadlock in ip6_finish_output2 Eric Dumazet
2013-11-30 17:49           ` David Miller

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